Basement membranes are specialized components of the extracellular matrix which may function as permeability barriers, supportive structures and may have an important role in the development and maintenance of normal tissue architecture. The objectives of this proposal are to characterize and examine the interactions of the macromolecular components (procollagen(s), proteoglycans, glycoproteins) of the lens capsule and Descemet's membrane of the rabbit eye, in order to understand better how the supramolecular organization of the basement membrane reflects its structure and function. Since these two basement membranes are synthesized by different cell types, a comparison of their macromolecular organization should lead to a better understanding of the structural and functional heterogeneity of basement membranes in general. To determine whether newly synthesized macromolecules are processed prior to deposition in the basement membrane matrix, we will study the biosynthesis of basement membrane components in cell and organ cultures of lens epithelium and corneal endothelium, using standard techniques, and compare the radiolabelled macromolecules with their counterparts in the intact basement membrane. The nature of the interacton among component macromolecules will be investigated systematically as follows: 1.) The ability of individual macromolecules to interact with each other will be assessed in a series of binding assays; 2.) The bonds between component macromolecules will be examined by sequential solubilization of isolated basement membranes in polar, non-polar, chaotropic, detergent solvents, prior to and after treatment with agents which disrupt specific covalent bonds; 3.) Autoradiography and histochemistry, prior to and after specific extractions and enzyme treatments, will be used to reveal topographic relationships and functional properties of the basement membrane components. This comprehensive approach will then be used to assess possible changes in the macromolecular organization of lens capsule and Descemet's membrane during development and in specific diseases which are expressed or experimentally inducible in rabbits; viz. bupthalmia, cataract, and experimental diabetes.